It is generally well known, in the mass transit vehicle art, that most railway passenger transit vehicles, such as trolleys, subway cars, and the like, are capable of being independently operated as a single passenger transit vehicle, and are often operated as a single vehicle, particularly during times when passenger travel is at a low volume. It is also generally well known, in this art, that there are times when such transit vehicles will be operated as a unit of two, three, or even more such transit vehicles joined together, particularly, during times of relatively high volume passenger travel, such as encountered during the morning and evening "rush hours".
Accordingly, in order to permit the operation of such multiple car units, such transit vehicles must be provided with a coupling arrangement at their forward and rearward ends for selectively joining and un-joining the transit vehicles together as the need dictates.
Most railway passenger transit vehicles, of the prior art, have utilized simple "hook-type" couplers for joining the adjacent ends of one such vehicle to another. These couplers are either pneumatically or hydraulically operated to uncouple the coupler incident to the disjoining of such joined adjacent ends of such railway transit vehicles. That is to say, the coupler hooks are normally spring biased to a coupling position, so that when the coupler on one transit vehicle is brought into contact with the coupler on another transit vehicle, the coupler hooks will automatically engage each other to effect a coupling.
The pneumatic or hydraulic control incorporates the required responsive hardware that merely re-positions the engaged hooks so that the two transit vehicles are not coupled together, thereby permitting either one of the transit vehicles to be moved relative to the other.
A new generation of railway passenger transit vehicles are coming into use which are entirely electric, and are not provided with a source of fluid pressure, pneumatic or hydraulic. For use in such a new generation of transit vehicles, it was therefore essential that couplers be designed that are entirely electrically operated as no fluid pressure would be available to operate such a coupler. These newer electrically operated couplers are not of the hook-type, and are not, therefore, compatible with the prior art hook-type couplers.
If a particular transit authority were only to utilize the newer generation of all electric transit vehicles, no problem would normally be encountered. However, there are a number of transit authorities which have been forced to replace only a portion of their transit vehicle fleet, so that both the newer and older generations of transit vehicles have be utilized on the same lines. As a result, such authorities have been handicapped by the inability of being able to couple together any pair of transit vehicles not of the same generation.
In addition to the above noted difficulties, the newer electrically operated couplers cannot readily be operated manually from outside the vehicle, as is often desired by repair and service personnel in a repair or service shop, for example. For this reason, any effort to manually uncouple a pair of joined electric transit vehicles is not a simple operation, but requires hardware removal. After such hardware removal, the coupling device must be reconstructed and reset so that it will again be functional as a coupler.
As oftentimes happens, however, such a reconstruction and resetting operation is overlooked or forgotten, so that when the transit vehicle is returned to service, the coupling device will not function until it is in fact properly reconstructed and reset. Unfortunately, such reconstruction and resetting may require that the transit vehicle be returned to the repair or service shop before it can be placed into service in a multiple car unit.